Synthesis of tetrasubstituted cyclopentadienes via palladium-catalyzed reaction of (Z)-2-En-4-yn acetates and N-methyl indoles

Article abstract of DOI:10.1021/jo3021055

An efficient approach for the synthesis of tetrasubstituted cyclopentadienes through Pd-catalyzed reactions of (Z)-2-en-4-yn acetates with substituted indoles was developed. This methodology has the advantages of broad scope, simple conditions and easily

Full text of DOI:10.1021/jo3021055

Note
pubs.acs.org/joc
Synthesis of Tetrasubstituted Cyclopentadienes via Palladium-
Catalyzed Reaction of (Z)‑2-En-4-yn Acetates and N‑Methyl Indoles
Mei-Jin Zhong,† Xiang-Chuan Wang,† Hai-Tao Zhu,† Jie Hu,† Lei Liu,† Xue-Yuan Liu,†
and Yong-Min Liang*,†,‡
†State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, PR China
‡State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000,
PR China
S
* Supporting Information
ABSTRACT: An efficient approach for the synthesis of
tetrasubstituted cyclopentadienes through Pd-catalyzed reac-
tions of (Z)-2-en-4-yn acetates with substituted indoles was
developed. This methodology has the advantages of broad
scope, simple conditions and easily accessible starting
materials.
Scheme 1. Model Reaction for the Formation of
Tetrasubstituted Cyclopentadiene
(Z)-2-En-4-yn-1-ols and their derivatives are important key
building blocks for diversity-oriented organic synthesis. Many
heterocycles such as dihydrofurans, furans,1−6 butenolides,7
phthalans,8,10,11 dihydroisoquinolines,9 isochromenes9−12 and
2-(1-alkenyl) furans13 have been synthesized by the intra-
molecular cyclization of this category of substrates. On the
other hand, the intermolecular cyclization of (Z)-enynols with
nucleophiles such as amines, furans and indoles catalyzed by
transition metals (Au, Ag, Cu and Bi) has been proved as an
effective method for the construction of heterocycles14−18 and
carbocycles.19−24 However, (Z)-enynol derivatives have never
been used for the construction of cyclopentadienes, which lend
themselves to the synthesis of fulvenes.25
cyclopenta-1,4-dienyl)-1H-indole 3aa in 86% yield (see
Supporting Information). Other Lewis acids did not promote
the transformation. Thus, the condition was selected as the
general conditions.
We used a range of (Z)-2-en-4-yn acetates 1 and N-methyl
indoles 2 to investigate the scopes and limits of this reaction.
The electronic effect of R1, R2, and R3 were examined by
employing a series of enynol acetates bearing electron-
withdrawing and electron-donating substituents to this reaction.
The results are summarized in Table 1. An electron-donating
substituent (Me) on the aryl group of R1 afforded the
corresponding product 3ba in 76% yield (entry 2), but
electron-withdrawing substituents (Cl, Br) on R1 lead to
lower yields (entries 3−4). Either an electron-withdrawing or
electron-donating substituent on aryl group of R2 resulted in a
moderate yield (51−64%, entries 5−7). However, a strong
electron-withdrawing substituent on R2 such as cyano group
had a negative effect on this reaction, which afforded a yield of
only 25% (entry 8). The electronic effect on R3 is similar to R1.
The reaction could proceed well when aryl group was
substituted by electron-donating substituents (Me, OMe)
(entries 9−10). The structure of 3ea and 3ia was
unambiguously confirmed by X-ray crystallographic analysis
(see Supporting Information). Moreover, when the substrate
Cyclopentadienes are useful not only as a reactive diene
component in the Diels−Alder reaction26−29 but also as a
precursor for the preparation of transition-metal complexes
with Cp-type ligands.30−33 The traditional method for the
synthesis of substituted cyclopentadiene is the reduction of
tetracyclone.34,35 Nevertheless, the development of synthetic
routes of tetrasubstituted cyclopentadienes under mild, simple
and neutral conditions remains an important synthetic goal.
Recently, Iwasawa et al. have reported a novel method for the
preparation of highly substituted cyclopentadiene derivatives
based on the Pt(II)-catalyzed cyclization of 1,2,4-trienes.24 This
work prompted us to examine possible synthesis of multi-
substituted cyclopentadienes by cyclization of (Z)-enynols,
which can be precursors of 1,2,4-trienes. Herein, we wish to
report an approach for the synthesis of tetrasubstituted
cyclopentadienes through Pd-catalyzed reactions of (Z)-2-en-
4-ynyl acetates with substituted indoles.
We commenced our studies by probing a variety of Pd
catalysts and solvents for the reaction between (Z)-1,3,5-
triphenylpent-2-en-4-ynyl acetate 1a and N-methyl indole 2a
(Scheme 1). To our delight, treatment of 1a and 2a (1.1 equiv)
in the presence of 10 mol % of PdCl2 in CH3CN at 80 °C for
0.5 h gave the desired product 1-methyl-3-(2,4,5-triphenyl-
Received: September 25, 2012
Published: November 7, 2012
© 2012 American Chemical Society
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Note
a
Table 1. PdCl2-Catalyzed Reactions of (Z)-2-En-4-yn acetates with N-Methyl Indole
b
entry
enynol acetate
R1
R2
R3
product
yield [%]
1
1a
1b
1c
1d
1e
1f
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
3aa
3ba
3ca
3da
3ea
3fa
86
76
51
62
60
64
51
25
76
71
64
57
45
62
40
50
2
p-MeC6H4
3
p-ClC6H4
4
p-BrC6H4
5
Ph
p-MeC6H4
6
Ph
p-BrC6H4
7
1g
1h
1i
Ph
p-ClC6H4
3ga
3ha
3ia
8
Ph
p-CNC6H4
9
Ph
Ph
p-MeC6H4
p-OMeC6H4
p-ClC6H4
n-C3H7
10
11
12
13
14
15
16
17
1j
Ph
Ph
3ja
1k
1l
Ph
Ph
3ka
3la
Ph
Ph
1m
1n
1o
1p
1q
Ph
Ph
o-MeC6H4
m-MeC6H4
Ph
3ma
3na
4oa
4pa
4qa
Ph
Ph
n-C3H7
Ph
2,4-dichloro-C6H4
Ph
p-ClC6H4
Ph
Ph
TMS
84
a
b
All of the reactions were carried out using 10 mol % of PdCl2 and 1.1 equiv of N-methyl indole at 80 °C in CH3CN, 0.1 mmol scale. Isolated
yields.
with C-5 alkyl substituent instead of aryl group was examined,
we obtained the expected product 3la in a moderate yield of
57% (entry 12). However, when substrates 1o, 1p and 1q were
used, only Fridel−Crafts arylation products were observed
(entries 15−17).
The present method could also be applied successfully to
various indoles. As shown in Table 2, electron-donating group
(Me, OMe) on C-5 position of N-methyl indole led to
moderate yields (60 and 50%, entries 1−2), but an electron-
withdrawing group such as Br could promote the reaction to
80% yield (entry 3). Even a cyano group could afford a yield of
71% (entry 4). C-7 substituted N-methyl indole was also
effective for the conversion (entry 5). Interestingly, when
unprotected indole 2g was used, the preconceived product 3ag
was also obtained in 68% yield (entry 6). Other substituted
indoles could also proceed the reaction, although the yields
were lower (enties 7−10).
We next applied this cyclization reaction to other
nucleophiles. When (Z)-1,3,5-triphenylpent-2-en-4-ynyl acetate
1a was treated with 1.2 equiv of CuX2, 10 mol % of Pd(acac)2
and 20 mol % of (C6F5)3P in 1,4-dioxane, the reaction proceed
smoothly to give the halogen-substituted cyclopentadienes 5a
and 6a, despite the yield being low (46 and 10%, Scheme 2).
Table 2. Reaction of (Z)-1,3,5-Triphenylpent-2-en-4-ynyl
a
Acetate 1a with Substituted Indoles
Scheme 2. Palladium-Catalyzed Reaction of (Z)-1,3,5-
Triphenylpent-2-en-4-ynyl Acetate 1a to Give Halogen
Substituted Cyclopentadienes 5a and 6a
b
entry
R4
R5
indole
product
yield [%]
1
2
3
4
5
6
7
8
9
10
5-CH3
5-OCH3
5-Br
CH3
CH3
CH3
CH3
CH3
H
2b
2c
2d
2e
2f
3ab
3ac
3ad
3ae
3af
60
50
80
73
71
5-CN
7-CH3
H
To understand the reaction mechanism, the arylate product
4aa has been isolated by heating 1a and 2a in CH3CN at 80 °C
(Scheme 3). The structure of 4aa can be confirmed by previous
work.17 The intramolecular cyclization of 4aa catalyzed by
PdCl2 proceeded smoothly to provide the same product of 3aa
as observed in the model reaction. The results indicate that 3
was formed through intermediate 4, and the formation of 4 was
not a Pd-catalyzed process. The structure of 3ea unambiguously
indicated that the reaction involves an indole-migration process.
c
2g
2h
2i
3ag
3ah
3ai
68
c
5-CH3
5-OCH3
5-Br
H
41
c
H
38
c
H
2j
3aj
50
c
7-CH3
H
2k
3ak
36
a
Unless noted, all of the reactions were carried out using 10 mol % of
PdCl2 and 1.1 equiv of substituted indole at 80 °C in CH3CN, 0.1
mmol scale. Isolated yields. The solvent is CH3NO2.
b
c
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Note
Scheme 3. Investigation of Possible Reaction Intermediates
Scheme 4. Reaction Mechanism of PdCl2-Catalyzed Tandem Reaction of (Z)-2-En-4-yn Acetates with N-Methyl Indole
were recorded on 100 MHz in CDCl3 using TMS as internal standard.
IR spectra were recorded on a FT-IR spectrometer, and only major
peaks are reported in cm. All new compounds were further
characterized by high-resolution mass spectrometry. HRMS was
obtained using a Q-TOF instrument equipped with APCI. Copies of
On the basis of the results above together with some
literature reports, the mechanism was envisioned (Scheme 4).
The reaction starts with the direct attack of indole 2a to
substrate 1. The C−C triple bond of the resulting Fridel-Crafts
arylation product 4 was activated by PdCl2 to form Pd(II)-
complex 7. A 6-endo-dig addition of the indole C-3 position
onto 7 results in the formation of a spirocyclic intermediate 8.
Then the C−C double bond migration leads to the C−C
fragmention of 8, which results in the formation of an achiral
pentadienyl cation intermediate 9.36 9 undergoes Nazarov-type
4π electrocyclization to afford palladium-carbene intermediate
10,24,37−40 which then undergoes a 1,2-indole migration to give
11 with regeneration of the palladium catalyst.41−49 The
structure of 3ea indicates that the migration group is indole.
Isomerization of 11 give the final product 3.
In summary, we have developed a PdCl2-catalyzed reaction
of (Z)-2-en-4-yn acetates with substituted indoles for the
synthesis of tetrasubstituted cyclopentadienes. The cyclo-
pentadiene formation proceeds through a Fridel−Crafts
arylation/1,5-indole migaration/Nazarov electrocyclization/
1,2-indole migration sequence. The method is mild, simple
and has wide applicability. Furthermore, we have succeed in
applying this cyclization reaction to other nucleophiles to give
the halogen substituted cyclopentadienes.
1
their H NMR and 13C NMR spectra are provided. Commercially
available reagents and solvents were used without further purification.
Starting Materials. (Z)-2-En-4-yn acetates were prepared
according to the literature.14 N-Methyl indoles were prepared
according to the literature.50
Typical Procedure for the Preparation of Tetrasubstituted
Cyclopentadienes. A mixture of (Z)-1,3,5-triphenylpent-2-en-4-ynyl
acetate 1a (0.1 mmol), N-methyl indole 2a (0.11 mmol), and PdCl2
(17.7 mg, 10 mol %) in CH3CN was stirred at 80 °C for 0.5 h. When
the reaction was considered complete as determined by TLC analysis,
the reaction was allowed to cool to room temperature and quenched
by water, and the mixture was extracted with EtOAc. The combined
organic layer was washed with saturated NH4Cl (aq), water and brine,
dried over Na2SO4 and filtered. The solvent was removed in vacuo,
and the crude product was purified by column chromatography to
afford 1-Methyl-3-(2,4,5-triphenyl-cyclopenta-1,4-dienyl)-1H-indole
3aa.
Characterization Data of Compounds. 1-Methyl-3-(2,4,5-
triphenyl-cyclopenta-1,4-dienyl)-1H-indole (3aa). Yellow oil, 36
mg, 86% yield: 1H NMR (400 MHz, CDCl3) δ 7.250−7.233 (t,
2H), 7.146−7.126 (d, J = 8 Hz, 3H), 7.102−7.097 (d, J = 2 Hz, 1H),
7.085−7.081 (d, J = 1.6 Hz, 1H), 7.065 (s, 1H), 7.055−7.026 (m, 5H),
7.014 (s, 1H), 6.995−6.978 (m, 2H), 6.967−6.965 (d, J = 0.8 Hz, 1H),
6.945−6.928 (m, 1H), 6.919−6.913 (d, J = 2.4 Hz, 1H), 6.777−6.738
(m, 1H), 6.272 (s, 1H), 4.019 (s, 2H), 3.507 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 145.6, 139.6, 139.3, 137.3, 137.2, 137.0, 136.7, 129.9,
128.6, 128.1, 128.0, 127.8, 127.3, 126.8, 126.6, 126.2, 126.0, 121.2,
121.1, 118.9, 110.3, 108.7, 45.7, 32.6; IR (neat, cm−1) 3433, 3052,
EXPERIMENTAL SECTION
■
General Remarks. Column chromatography was carried out on
silica gel using EtOAc and petroleum ether as solvents. 1H NMR
spectra were recorded on 400 MHz in CDCl3, and 13C NMR spectra
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Note
2924, 1599, 1484, 1378, 1330, 1239, 1070, 1021, 742, 696, 408;
HRMS (APCI) Calcd for C32H26N M + H = 424.2060, found
424.2061.
2359, 1646, 1483, 1384, 1090, 1017, 822, 742, 696, 408; HRMS
(APCI) Calcd for C32H25ClN M + H = 458.1670, found 458.1674.
4-[2-(1-Methyl-1H-indol-3-yl)-3,4-diphenyl-cyclopenta-1,3-dien-
1
yl]-benzonitrile (3ha). Yellow oil, 11 mg, 25% yield: H NMR (400
3-(2,5-Diphenyl-4-p-tolyl-cyclopenta-1,4-dienyl)-1-methyl-1H-in-
dole (3ba). Brown oil, 33 mg, 76% yield: 1H NMR (400 MHz,
CDCl3) δ 7.388−7.370 (d, J = 7.2 Hz, 2H), 7.284−7.263 (m, 1H),
7.195−7.185 (m, 4H), 7.166 (s, 2H), 7.149 (s, 1H), 7.132 (s, 1H),
7.115 (s, 1H), 7.097−7.032 (m, 5H), 6.917−6.880 (t, J = 7.2 Hz, 1H),
6.411 (s, 1H), 4.140 (s, 2H), 3.642 (s, 3H), 2.337 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ 144.9, 139.3, 139.2, 137.4, 137.3, 137.0, 136.7,
135.9, 133.8, 129.9, 128.8, 128.6, 128.0, 127.8, 127.7, 127.2, 126.8,
126.5, 125.9, 121.2, 121.1, 118.9, 110.4, 108.7, 45.7, 32.6, 21.1; IR
(neat, cm−1) 3827, 3433, 2923, 1621, 1461, 1380, 1260, 1096, 1029,
805, 740, 698, 407; HRMS (APCI) Calcd for C33H28N M + H =
438.2216, found 438.2223.
3-[4-(4-Chloro-phenyl)-2,5-diphenyl-cyclopenta-1,4-dienyl]-1-
methyl-1H-indole (3ca). Yellow oil, 23 mg, 51% yield: 1H NMR (400
MHz, CDCl3) δ 7.317−7.300 (d, J = 6.8 Hz, 2H), 7.227−7.205 (d, J =
8.8 Hz, 1H), 7.158−7.025 (m, 12H), 6.988−6.969 (m, 2H), 6.851−
6.814 (t, J = 7.2 Hz, 1H), 6.339 (s, 1H), 4.053 (s, 2H), 3.587 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 146.2, 139.8, 137.9, 137.0, 137.0,
136.9, 136.7, 135.1, 131.8, 129.7, 129.0, 128.6, 128.2, 128.0, 127.2,
126.8, 126.7, 126.2, 121.2, 121.1, 118.9, 110.1, 108.8, 45.5, 32.7; IR
(neat, cm−1) 3827, 3441, 3053, 2941, 2327, 1485, 1383, 1091, 1013,
821, 741, 697, 470; HRMS (APCI) Calcd for C32H25ClN M + H =
458.1670, found 458.1674.
3-[4-(4-Bromo-phenyl)-2,5-diphenyl-cyclopenta-1,4-dienyl]-1-
methyl-1H-indole (3da). Deep yellow oil, 31 mg, 62% yield: 1H NMR
(400 MHz, CDCl3) δ 7.316−7.298 (d, J = 7.2 Hz, 2H), 7.216−7.199
(d, J = 6.8 Hz, 1H), 7.154−7.112 (m, 8H), 7.088−7.026 (m, 4H),
6.990−6.969 (dd, J1 = 6.8 Hz, J2 = 1.6 Hz, 2H), 6.850−6.812 (t, J = 7.6
Hz, 1H), 6.337 (s, 1H), 4.048 (s, 2H), 3.576 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 146.2, 139.8, 137.9, 137.0, 137.0, 136.9, 136.7, 135.1,
131.8, 129.7, 129.0, 128.6, 128.2, 128.0, 127.2, 126.8, 126.7, 126.2,
121.2, 121.1, 118.9, 110.1, 108.8, 45.5, 32.6; IR (neat, cm−1) 3827,
3435, 3053, 2928, 2318, 1600, 1566, 1486, 1379, 1335, 1264, 1207,
1093, 1018, 821, 140, 698, 407; HRMS (APCI) Calcd for C32H25BrN
M + H = 502.1165, found 502.1167.
MHz, CDCl3) δ 7.378−7.356 (d, J = 8.8 Hz, 2H), 7.328−7.307 (d, J =
8.4 Hz, 2H), 7.254−7.114 (m, 10 H), 6.987−6.969 (m, 3H), 6.887−
6.850 (t, J = 7.2 Hz, 1H), 6.328 (s 1H), 4.083 (s, 2H), 3.595 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 145.6, 141.6, 141.2, 140.6, 136.7,
136.7, 136.1, 131.8, 129.8, 128.7, 128.2, 128.0, 127.8, 127.3, 126.9,
126.7, 126.1, 121.6, 120.8, 119.38, 119.35, 109.5, 109.1, 108.6; IR
(neat, cm−1) 3828, 3742, 3442, 2359, 2222, 1646, 1511, 1463, 1384,
1097, 1021, 834, 743, 693, 407; HRMS (APCI) Calcd for C33H25N2 M
+ H =449.2012, found 449.2022.
3-(2,4-Diphenyl-5-p-tolyl-cyclopenta-1,4-dienyl)-1-methyl-1H-in-
dole (3ia). Yellow oil, 33 mg, 76% yield: 1H NMR (400 MHz, CDCl3)
δ 7.305−7.287 (d, J = 7.2 Hz, 2H), 7.222−7.107 (m, 5H), 7.090−
6.992 (m, 6H), 6.920−6.865 (q, J = 8 Hz, 4H), 6.848−6.811 (t, J = 7.6
Hz, 1H), 6.359 (s, 1H), 4.068 (s, 2H), 3,549 (s, 3H), 2.243 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 145.5, 139.6, 139.1, 137.3, 137.1,
136.8, 136.7, 136.1, 134.1, 129.7, 128.58, 128.55, 128.0, 127.9, 127.8,
127.2, 126.9, 126.1, 126.0, 121.1, 118.9, 110.4, 108.7, 45.7, 32.6, 21.2.
IR (neat, cm−1) 3829, 3743, 3437, 3053, 2920, 2360, 1684, 1611, 1518,
1463, 1375, 1333, 1074, 823, 743, 695, 407; HRMS (APCI) Calcd for
C33H28N M + H = 438.2216, found 438.2223.
3-[5-(4-Methoxy-phenyl)-2,4-diphenyl-cyclopenta-1,4-dienyl]-1-
methyl-1H-indole (3ja). Yellow oil, 32 mg, 71% yield: 1H NMR (400
MHz, CDCl3) δ 7.315−7.294 (m, 2H), 7.238−7.213 (m, 3H), 7.186−
7.149 (m, 2H), 7.126−7.027 (m, 6H), 6.922−6.894 (dd, J1 = 8.8 Hz, J2
= 2.4 Hz, 2H), 6.861−6.822 (t, J = 8 Hz, 1H), 6.672−6.650 (d, J = 8.8
Hz, 2H), 6.382 (s, 1H), 4.068 (s, 2H), 3.719 (s, 3H), 3.605 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 158.3, 145.1, 139.6, 139.0, 137.3,
137.1, 136.9, 136.7, 131.0, 129.5, 128.6, 128.1, 128.0, 127.8, 127.2,
126.9, 126.1, 126.0, 121.2, 121.1, 118.9, 113.3, 110.4, 108.8, 55.0, 45.6,
32.7; IR (neat, cm−1) 3845, 3742, 3436, 2360, 1691, 1646, 1611, 1512,
1463, 1383, 1244, 1098, 1032, 835, 744, 693, 407; HRMS (APCI)
Calcd for C33H28NO M + H = 454.2165, found 454.2180.
3-[5-(4-Chloro-phenyl)-2,4-diphenyl-cyclopenta-1,4-dienyl]-1-
methyl-1H-indole (3ka). Brown amorphous solid, 29 mg, 64% yield:
1H NMR (400 MHz, CDCl3) δ 7.230−7.209 (m, 2H), 7.173−7.145
3-(4,5-Diphenyl-2-p-tolyl-cyclopenta-1,4-dienyl)-1-methyl-1H-in-
dole (3ea). Yellow oil, 26 mg, 60% yield: 1H NMR (400 MHz,
CDCl3) δ 7.226−7.197 (m, 5H), 7.173−7.155 (d, J = 7.2 Hz, 2H),
7.134−7.078 (m, 7H), 7.003−6.981 (dd, J1 = 7.2 Hz, J2 = 1.6 Hz, 2H),
6.910−6.890 (d, J = 8 Hz, 2H), 6.872−6.835 (t, J = 7.2 Hz, 1H), 6.358
(s, 1H), 4.073 (s, 2H), 3.586 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
145.6, 139.8, 138.8, 137.3, 136.7, 136.7, 136.3, 135.7, 134.3, 129.9,
128.7, 128.5, 128.1, 127.8, 127.8, 127.1, 127.0, 126.6, 126.1, 121.2,
121.1, 118.9, 110.5, 108.7, 45.7, 32.6, 21.1; IR (neat, cm−1) 3439,
3053, 2922, 2322, 1621, 1496, 1475, 1379, 1332, 1264, 1072, 1022,
812, 738, 699, 407; HRMS (APCI) Calcd for C33H28N M + H =
438.2216, found 438.2225.
(m, 1H), 7.117−7.107 (d, J = 4 Hz, 4H), 7.086−6.966 (m, 8H),
6.854−6.833 (d, J = 7.6 Hz, 2H), 6.799−6.762 (t, J = 7.2 Hz, 1H),
6.320 (s, 1H), 4.002 (s, 2H), 3.556 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 144.1, 140.2, 140.0, 137.0, 136.8, 136.5, 136.4, 135.6, 132.5,
131.3, 128.3, 128.2, 128.1, 128.0, 127.9, 127.2, 126.8, 126.5, 126.2,
121.4, 120.9, 119.1, 110.2, 108.9, 45.9, 32.7; IR (neat, cm−1) 3440,
2928, 1627, 1485, 1381, 1089, 911, 833, 740, 696; HRMS (APCI)
Calcd for C32H25ClN M + H = 458.1670, found 458.1673.
3-(2,4-Diphenyl-5-propyl-cyclopenta-1,4-dienyl)-1-methyl-1H-in-
1
dole (3la). Deep yellow oil, 22 mg, 57% yield: H NMR (400 MHz,
CDCl3) δ 7.491−7.470 (m, 2H), 7.410−7.330 (m, 6H), 7.260−7.207
(m, 6H), 6.079−6.990 (m, 4H), 6.951 (s, 1H), 3.917 (s, 2H), 3.834 (s,
3H), 2.428−2.388 (t, J = 8 Hz, 2H), 1.287−1.192 (m, 2H), 0.663−
0.627 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 145.7,
141.2, 138.2, 138.0, 137.6, 137.0, 128.4, 128.0, 127.8, 127.6, 127.0,
126.9, 126.0, 125.8, 121.5, 120.6, 119.2, 111.2, 109.0, 45.6, 32.9, 29.1,
22.7, 14.2; IR (neat, cm−1) 3435, 1635, 1374, 1101, 687; HRMS
(APCI) Calcd for C29H28N M + H = 390.2216, found 390.2222.
3-(2,4-Diphenyl-5-o-tolylcyclopenta-1,4-dienyl)-1-methyl-1H-in-
dole (3ma). Yellow oil, 20 mg, 45% yield: 1H NMR (400 MHz,
CDCl3) δ 7.327−7.308 (d, J = 8.4 Hz, 2H), 7.236−7.111 (m, 6H),
7.094−7.051 (m, 6H), 7.026−6.987 (t, J = 7.6 Hz, 1H), 6.952−6.933
(d, J = 7.6 Hz, 1H), 6.850−6.786 (dd, J1 = 18 Hz, J2 = 7.6 Hz, 3H),
6.348 (s, 1H), 4.080 (s, 2H), 3.564 (s, 3H), 2.119 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ 145.8, 139.4, 139.0, 137.3, 137.2, 137.2, 137.1,
136.7, 136.7, 130.4, 128.6, 128.0, 128.0, 128.0, 127.3, 127.2, 127.0,
126.9, 126.1, 126.0, 121.2, 121.1, 118.8, 110.4, 108.7, 45.6, 32.6, 32.6,
21.3, 21.3; IR (neat, cm−1) 3436, 3052, 3013, 2925, 1597, 1487, 1379,
1335, 1214, 1070, 1032, 797, 751, 695, 524; HRMS (APCI) Calcd for
C33H28N M + H = 438.2216, found 438.2221.
3-[2-(4-Bromo-phenyl)-4,5-diphenyl-cyclopenta-1,4-dienyl]-1-
methyl-1H-indole (3fa). Deep yellow oil, 32 mg, 64% yield: 1H NMR
(400 MHz, CDCl3) δ 7.233−7.175 (m, 7H), 7.157−7.090 (m, 7H),
7.056−7.036 (d, J = 8 Hz, 1H), 6.989−6.966 (dd, J1 = 7.2 Hz, J2 = 1.6
Hz, 2H), 6.892−6.854 (t, J = 7.6 Hz, 1H), 6.331 (s, 1H), 4.042 (s,
2H), 3.581 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 145.5, 139.6,
138.0, 137.8, 137.0, 136.7, 136.5, 136.1, 131.1, 129.8, 128.7, 128.6,
128.1, 127.9, 127.8, 126.7, 126.5, 126.4, 121.3, 121.0, 119.7, 119.1,
109.9, 108.9, 45.5, 32.7; IR (neat, cm−1) 3828, 3743, 3436, 3053, 2921,
2358, 1482, 1383, 1336, 1204, 1072, 1016, 816, 741, 696, 407; HRMS
(APCI) Calcd for C32H25BrN M + H = 502.1165, found 502.1166.
3-[2-(4-Chloro-phenyl)-4,5-diphenyl-cyclopenta-1,4-dienyl]-1-
methyl-1H-indole (3ga). Yellow oil, 23 mg, 51% yield: 1H NMR (400
MHz, CDCl3) δ 7.390−7.326 (q, J = 8.4 Hz, 4H), 7.246−7.227 (m,
2H), 7.207−7.202 (d, J = 2 Hz, 2H), 7.182−7.126 (m, 6H), 6.989−
6.969 (d, J = 8 Hz, 3H), 6.896−6.859 (t, J = 7.6 Hz, 1H), 6.332 (s,
1H), 4.101 (s, 2H), 3.618 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
145.6, 141.6 141.3, 140.7, 136.8, 136.7, 136.1, 131.8, 129.9, 128.8,
128.2, 128.0, 127.9, 127.3, 126.9, 126.8, 126.1, 121.6, 120.8, 119.4,
109.6, 109.1, 108.6, 45.3, 32.7; IR (neat, cm−1) 3828, 3742, 3443,
10958
dx.doi.org/10.1021/jo3021055 | J. Org. Chem. 2012, 77, 10955−10961

The Journal of Organic Chemistry
Note
3-(2,4-Diphenyl-5-m-tolylcyclopenta-1,4-dienyl)-1-methyl-1H-in-
dole (3na). Yellow oil, 27 mg, 62% yield: 1H NMR (400 MHz,
CDCl3) δ 7.323−7.304 (d, J = 7.9 Hz, 2H), 7.231−7.124 (m, 5H),
7.085−6.981 (m, 7H), 6.945−6.927 (d, J = 7.2 Hz, 1H), 6.830−6.786
(m, 3H), 6.343 (s, 1H), 4.072 (s, 2H), 3.541 (s, 3H), 2.111 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 145.8, 139.4, 139.0, 137.3, 137.2,
137.2, 137.1, 136.7, 136.7, 130.4, 128.6, 128.0, 128.0, 127.7, 127.7,
127.3, 127.2, 127.0, 126.9, 126.1, 126.0, 121.2, 121.1, 118.8, 110.4,
108.7, 45.6, 32.6, 32.5, 21.3, 21.2; IR (neat, cm−1) 3436, 3052, 3019,
2923, 1596, 1487, 1379, 1333, 1214, 1070, 1032, 797, 751, 694, 523;
HRMS (APCI) Calcd for C33H28N M + H = 438.2216, found
438.2218.
109.7, 108.3, 45.7, 32.6, 21.2; IR (neat, cm−1) 3439, 1633, 1495, 1440,
1379, 1254, 1063, 699; HRMS (APCI) Calcd for C33H28N M + H =
438.2216, found 438.2224.
5-Methoxy-1-methyl-3-(2,4,5-triphenyl-cyclopenta-1,4-dienyl)-
1
1H-indole (3ac). Deep yellow oil, 22 mg, 50% yield: H NMR (400
MHz, CDCl3) δ 7.332−7.313 (d, J = 7.6 Hz, 2H), 7.233−7.226 (d, J =
2.8 Hz, 1H), 7.207 (s, 1H), 7.185−7.125 (m, 5H), 7.118−7.090 (m,
4H), 7.068−7.031 (m, 3H), 6.748−6.720 (dd, J1 = 8.8 Hz, J2 = 2.4 Hz,
1H), 6.387−6.382 (d, J = 2 Hz, 1H), 6.265 (s, 1H), 4.098 (s, 2H),
3.549 (s, 3H), 3.410 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 153.5,
145.3, 139.6, 138.9, 137.6, 137.3, 137.0, 136.7, 131.9, 130.0, 129.3,
128.1, 128.0, 127.9, 127.8, 127.4, 126.8, 126.7, 126.2, 126.0, 111.9,
109.6, 109.5, 102.5, 55.3, 45.9, 32.8; IR (neat, cm−1) 3434, 2912, 2360,
1629, 1489, 1437, 1381, 1216, 1146, 1098, 1029, 741, 695, 613;
HRMS (APCI) Calcd for C33H28NO M + H = 454.2165, found
454.2181.
(Z)-1-Methyl-3-(1,3,5-triphenylpent-2-en-4-ynyl)-1H-indole (4aa).
1
Yellow oil, 31 mg, 75% yield: H NMR (400 MHz, CDCl3) δ 7.709−
7.687 (m, 2H), 7.537−7.496 (m, 3H), 7.437−7.419 (d, J = 7.2 Hz,
2H), 7.344−7.307 (m, 6H), 7.287−7.234 (m, 3H), 7.219−7.171 (m,
2H), 7.035−6.996 (m, 1H), 6.916−6.891 (d, J = 10 Hz, 1H), 6.788 (s,
1H), 5.846−5.821 (d, J = 10 Hz, 1H), 3.691 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 143.4, 139.8, 138.1, 137.5, 131.7, 128.6, 128.5, 128.3,
127.8, 127.4, 127.0, 127.0, 126.5, 126.4, 123.5, 123.0, 121.8, 120.1,
119.1, 116.8, 109.3, 95.9, 86.9, 44.7, 44.7, 32.8, 32.7; IR (neat, cm−1)
3457, 3055, 2925, 1596, 1487, 1380, 1339, 1239, 1211, 1147, 1124,
1084, 1062, 1022, 885, 798, 750, 694, 571; HRMS (APCI) Calcd for
C32H26N M + H = 424.2060, found 424.2061.
5-Bromo-1-methyl-3-(2,4,5-triphenyl-cyclopenta-1,4-dienyl)-1H-
1
indole (3ad). Yellow oil, 40 mg, 80% yield: H NMR (400 MHz,
CDCl3) δ 7.283−7.266 (d, J = 6.8 Hz, 2H), 7.209−7.190 (d, J = 7.6
Hz, 2H), 7.159−7.057 (m, 11H), 7.004−6.985 (d, J = 7.6 Hz, 3H),
6.361 (s, 1H), 4.062 (s, 2H), 3.495 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 145.1, 140.3, 139.4, 137.1, 136.9, 136.5, 136.3, 135.3, 129.7,
129.5, 128.5, 128.1, 127.9, 127.8, 127.3, 126.7, 126.3, 124.0, 123.5,
112.4, 110.3, 110.1, 45.7, 32.8; IR (neat, cm−1) 3440, 2921, 2360,
1622, 1478, 1382, 1145, 1053, 908, 788, 751, 696, 598; HRMS (APCI)
Calcd for C32H25BrN M + H = 502.1165, found 502.1166.
3-(3,5-Diphenyl-1-propyl-pent-2-en-4-ynyl)-1-methyl-1H-indole
1
(4oa). Yellow oil, 16 mg, 40% yield: H NMR (400 MHz, CDCl3) δ
1-Methyl-3-(2,4,5-triphenyl-cyclopenta-1,4-dienyl)-1H-indole-5-
carbonitrile (3ae). Brown oil, 32 mg, 73% yield: 1H NMR (400 MHz,
CDCl3) δ 7.227−7.202 (dd, J1 = 8.8 Hz, J2 = 1.6 Hz, 1H), 7.179−
7.108 (m, 6H), 7.091−7.010 (m, 9H), 6.920−6.897 (m, 2H), 6.428 (s,
1H), 4.021 (s, 2H), 3.546 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
144.7, 141.0, 139.8, 138.0, 136.9, 136.7, 136.3, 135.4, 130.5, 129.7,
128.2, 128.1, 128.1, 127.7, 127.3, 126.9, 126.6, 126.5, 126.4, 124.3,
120.6, 111.6, 109.8, 102.0, 45.8, 32.9; IR (neat, cm−1) 3434, 2360,
2220, 1629, 1490, 1448, 1382, 1145, 1098, 800, 737, 696, 660, 605;
HRMS (APCI) Calcd for C33H25N2 M + H = 449.2012, found
449.2021.
7.846−7.826 (d, J = 8.0 Hz, 1H), 7.657−7.638 (d, J = 7.6 Hz, 2H),
7.586−7.563 (dd, J1 = 8 Hz, J2 = 1.6 Hz, 2H), 7.374−7.175 (m, 9H),
7.087−7.049 (t, J = 7.6 Hz, 1H), 6.911 (s, 1H), 6.506−6.481 (d, J = 10
Hz, 1H), 4.552−4.490 (td, J1= 7.4 Hz, J2 = 6 Hz, 1H), 3.722 (s, 3H),
2.067−1.867 (m, 2H), 1.576−1.459 (m, 2H), 1.022−0.985 (t, J = 7.6
Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 142.5, 138.2, 137.2, 131.6,
128.5, 128.3, 128.3, 127.6, 127.5, 126.2, 125.2, 123.7, 122.3, 121.6,
119.9, 118.9, 117.6, 109.2, 95.3, 87.4, 38.6, 37.4, 32.7, 20.9, 14.3; IR
(neat, cm−1) 3435, 3037, 2957, 2143, 1635, 1253, 1374, 1101, 908,
871, 844, 735, 699, 687; HRMS (APCI) Calcd for C29H28N M + H =
390.2216, found 390.2213.
1,7-Dimethyl-3-(2,4,5-triphenyl-cyclopenta-1,4-dienyl)-1H-indole
(Z)-3-(3-(4-Chlorophenyl)-1-(2,4-dichlorophenyl)-5-phenylpent-
1
(3af). Brown oil, 31 mg, 71% yield: H NMR (400 MHz, CDCl3) δ
2-en-4-yn-1-yl)-1-methyl-1H-indole (4pa). Yellow oil, 26 mg, 50%
1
7.247−7.227 (d, J = 8 Hz, 2H), 7.138−7.119 (d, J = 7.6 Hz, 3H),
7.097−6.998 (m, 8H), 6.975−6.958 (d, J = 6.8 Hz, 1H), 6.928−6.907
(m, 2H), 6.851−6.832 (d, J = 7.6 Hz, 1H), 6.713−6.695 (d, J = 7.2 Hz,
1H), 6.631−6.593 (t, J = 7.6 Hz, 1H), 6.157 (s, 1H), 4.007 (s, 2H),
3.747 (s, 3H), 2.623 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 145.7,
139.6, 139.2, 137.3, 137.2, 137.0, 136.7, 135.4, 130.1, 129.9, 128.1,
128.0, 127.9, 127.8, 127.8, 127.2, 126.6, 126.2, 126.0, 124.0, 120.6,
119.3, 110.1, 45.6, 36.6, 36.57, 19.7; IR (neat, cm−1) 3434, 3053, 2922,
2360, 1600, 1488, 1450, 1373, 1263, 1204, 1073, 1032, 854, 745, 696;
HRMS (APCI) Calcd for C33H28N M + H = 438.2216, found
438.2223.
yield: H NMR (400 MHz, CDCl3) δ 7.625−7.604 (d, J = 8.4 Hz,
2H), 7.503−7.471 (m, 3H), 7.435−7.430 (d, J = 2 Hz, 1H), 7.311−
7.277 (m, 6H), 7.221−7.159 (m, 3H), 7.059−7.022 (d, J = 7.2 Hz,
1H), 6.766−6.742 (d, J = 9.6 Hz, 1H), 6.657 (s, 1H), 6.202−6.178 (d,
J = 9.6 Hz, 1H), 3.685 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 139.6,
138.1, 137.4, 136.2, 134.7, 133.8, 132.7, 131.6, 130.4, 129.6, 128.6,
128.5, 128.4, 127.6, 127.3, 126.9, 126.8, 123.6, 122.9, 121.9, 119.6,
119.2, 115.7, 109.3, 97.1, 85.8, 41.0, 32.7, 32.7; IR (neat, cm−1) 3458,
3052, 2923, 1596, 1487, 1458, 1380, 1337, 1239, 1214, 1149, 1124,
1084, 1062, 1022, 885, 798, 750, 694, 571; HRMS (APCI) Calcd for
C32H23Cl3N M + H = 526.0891, found 526.0888.
3-(2,4,5-Triphenyl-cyclopenta-1,4-dienyl)-1H-indole (3ag). Brown
(Z)-3-(1,3-Diphenyl-5-(trimethylsilyl)pent-2-en-4-ynyl)-1-methyl-
1
1
oil, 28 mg, 68% yield: H NMR (400 MHz, CDCl3) δ 7.865 (s, 1H),
1H-indole (4qa). Yellow oil, 35 mg, 84% yield: H NMR (400 MHz,
7.322−7.301 (m, 2H), 7.268−7.247 (d, J = 8.4 Hz, 3H), 7.231−7.205
(m, 2H), 7.186−7.047 (m, 9H), 7.014−6.990 (m, 2H), 6.874−6.837
(t, J = 7.2 Hz, 1H), 6.519−6.513 (d, J = 2.4 Hz, 1H), 4.110 (s, 2H);
13C NMR (100 MHz, CDCl3) δ 145.5, 140.1, 139.4, 137.2, 137.0,
136.9, 136.6, 135.7, 129.8, 128.1, 128.0, 127.9, 127.8, 127.2, 126.6,
126.3, 126.3, 126.1, 123.8, 121.7, 120.9, 119.4, 112.0, 110.7, 45.7; IR
(neat, cm−1) 3434, 3052, 2924, 2322, 1685, 1616, 1456, 1382, 1258,
1199, 1093, 800, 747, 697, 605; HRMS (APCI) Calcd for C31H24N M
+ H = 410.1903, found 410.1905.
CDCl3) δ 7.752−7.734 (d, J = 7.2 Hz, 2H), 6.656−6.636 (d, J = 8 Hz,
1H), 7.531−7.512 (d, J = 7.6 Hz, 2H), 7.445−7.270 (m, 8H), 7.169−
7.132 (t, J = 7.6 Hz, 1H), 7.018−6.992 (d, J = 10.4 Hz, 1H), 6.867 (s,
1H), 5.909−5.884 (d, J = 10 Hz, 1H), 3.800 (s, 3H), 0.406 (s, 9H);
13C NMR (100 MHz, CDCl3) δ 143.3, 140.6, 137.6, 137.4, 128.5,
128.3, 128.2, 127.7, 127.3, 126.8, 126.4, 126.2, 122.9, 121.7, 120.1,
118.9, 116.8, 109.2, 102.3, 101.3, 44.4, 32.6, 0.1; IR (neat, cm−1) 3058,
3027, 2958, 2926, 2854, 2248, 2145, 1062, 1545, 1473, 1373, 1331,
1251, 1012, 987, 908, 871, 843, 735, 699, 646; HRMS (APCI) Calcd
for C29H30NSi M + H = 420.2142, found 420.2143.
5-Methyl-3-(2,4,5-triphenyl-cyclopenta-1,4-dienyl)-1H-indole
1
(3ah). Yellow oil, 17 mg, 41% yield: H NMR (400 MHz, CDCl3) δ
1,5-Dimethyl-3-(2,4,5-triphenyl-cyclopenta-1,4-dienyl)-1H-indole
1
(3ab). Brown oil, 26 mg, 60% yield: H NMR (400 MHz, CDCl3) δ
7.783 (s, 1H), 7.327−7.309 (d, J = 7.2 Hz, 2H), 7.231−7.050 (m,
12H), 7.016−7.003 (d, J = 5.2 Hz, 2H), 6.905−6.885 (d, J = 8 Hz,
1H), 6.843 (s, 1H), 6.489 (s, 1H), 4.104 (s, 2H), 2.188 (s, 3H); 13C
NMR (100 MHz, CDCl3) δ 145.5, 140.0, 139.3, 137.3, 137.2, 136.7,
134.1, 129.8, 128.5, 128.1, 128.0, 127.9, 127.8, 127.3, 126.7, 126.6,
126.2, 126.1, 123.9, 123.3, 120.7, 111.5, 110.2, 45.7, 21.3; IR (neat,
cm−1) 3435, 3052, 2924, 2323, 1633, 1496, 1443, 1379, 1254, 1063,
7.147−7.129 (m, 2H), 7.101−7.084 (d, J = 6.8 Hz, 2H), 7.064−7.044
(m, 2H), 7.030−6.969 (m, 8H), 6.943−6.920 (dd, J1 = 7.2 Hz, J2 = 2
Hz, 2H), 6.851−6.830 (d, J = 8.4 Hz, 1H), 6.229 (s, 1H), 4.012 (s,
2H), 3.470 (s, 3H), 2.103 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
145.6, 139.4, 139.2, 137.3, 137.3, 137.2, 136.7, 135.1, 129.9, 128.6,
128.1, 127.9, 127.8, 127.3, 127.1, 126.6, 126.2, 125.9, 122.7, 120.9,
10959
dx.doi.org/10.1021/jo3021055 | J. Org. Chem. 2012, 77, 10955−10961

The Journal of Organic Chemistry
Note
800, 745, 699; HRMS (APCI) Calcd for C32H26N M + H = 424.2060,
found 424.2065.
ACKNOWLEDGMENTS
■
The authors gratefully acknowledge National Basic Research
Program of China (973 program) and “111” program of MOE.
We thank the NSF (NSF-21072080, NSF-20732002) for
financial support.
Methoxy-3-(2,4,5-triphenyl-cyclopenta-1,4-dienyl)-1H-indole
1
(3ai). Yellow oil, 17 mg, 38% yield: H NMR (400 MHz, CDCl3) δ
7.798 (s, 1H), 7.318−7.300 (d, J = 7.2 Hz, 2H), 7.229−7.026 (m, 14
H), 6.721−6.694 (dd, J1 = 8.8 Hz, J2 = 2 Hz, 1H), 6.452−6.418 (dd, J1
= 11.2 Hz, J2 = 2.4 Hz, 2H), 4.105 (s, 2H), 3.428 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ 153.7, 145.2, 139.6, 137.5, 137.3, 136.9, 130.7,
129.9, 128.09, 128.06, 128.0, 127.8, 127.4, 126.7, 126.5, 126.3, 126.1,
124.7, 112.5, 111.6, 111.3, 102.2, 55.3, 45.8; IR (neat, cm−1) 3434,
2911, 2357, 1631, 1491, 1442, 1383, 1216, 1147, 1098, 1029, 741, 699,
608; HRMS (APCI) Calcd for C32H26NO M + H = 440.2009, found
440.2019.
REFERENCES
■
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5409.
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(3) Gabriele, B.; Salerno, G. Chem. Commun. 1997, 1083.
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(6) Gabriele, B.; Plastina, P.; Salerno, G; Mancuso, R. Synthesis 2006,
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(8) Praveen, C.; Iyyappan, C.; Perumal, P. T. Tetrahedron Lett. 2010,
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5-Bromo-3-(2,4,5-triphenyl-cyclopenta-1,4-dienyl)-1H-indole
1
(3aj). Yellow oil, 24 mg, 50% yield: H NMR (400 MHz, CDCl3) δ
7.877 (s, 1H), 7.289−7.266 (dd, J1 = 7.6 Hz, J2 = 1.6 Hz, 2H), 7.223−
7.073 (m, 14H), 7.008−6.985 (m, 2H), 6.540−6.534 (d, J = 2.4 Hz,
1H), 4.090 (s, 2H); 13C NMR (100 MHz, CDCl3) δ 145.1, 140.8,
139.5, 137.1, 136.8, 136.5, 136.2, 134.3, 129.7, 128.2, 128.1, 128.0,
127.8, 127.3, 126.7, 126.4, 126.3, 124.9, 124.6, 123.4, 112.8, 112.2,
111.8, 45.7; IR (neat, cm−1) 3443, 2922, 2355, 1622, 1478, 1387, 1144,
1057, 908, 788, 751, 696, 601; HRMS (APCI) Calcd for C31H23BrN
M + H = 488.1008, found 488.1010.
7-Methyl-3-(2,4,5-triphenyl-cyclopenta-1,4-dienyl)-1H-indole
1
(3ak). Yellow oil, 15 mg, 36% yield: H NMR (400 MHz, CDCl3) δ
7.819 (s, 1H), 7.316−7.298 (d, J = 7.2 Hz, 2H), 7.239−7.043 (m,
11H), 7.019−6.996 (dd, J1 = 7.6 Hz, J2 = 2 Hz, 2H), 6.949−6.929 (d, J
= 8 Hz, 1H), 6.895−6.878 (d, J = 6.8 Hz, 1H), 6.793−6.755 (t, J = 7.6
Hz, 1H), 6.514−6.508 (d, J = 2.4 Hz, 1H), 4.107 (s, 2H), 2.421 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 145.5, 140.0, 139.4, 137.3,
137.1, 137.1, 136.7, 135.4, 129.9, 128.1, 128.0, 127.9, 127.8, 127.2,
126.6, 126.2, 126.1, 125.9, 123.6, 122.3, 119.7, 119.5, 118.8, 112.4,
45.7, 16.6; IR (neat, cm−1) 3434, 3053, 2922, 2358, 1611, 1489, 1450,
1380, 1265, 1204, 1073, 1040, 847, 748, 696; HRMS (APCI) Calcd for
C32H26N M + H = 424.2060, found 424.2066.
(3-Chlorocyclopenta-1,3-diene-1,2,4-triyl)tribenzene (5a). Yellow
oil, 29 mg, 46% yield (0.2 mmol scale): 1H NMR (400 MHz, CDCl3)
δ 7.830−7.811 (d, J = 7.6 Hz, 2H), 7.428−7.284 (m, 8H), 7.230−
7.125 (m, 5H), 3.939 (s, 2H); 13C NMR (100 MHz, CDCl3) δ 141.9,
139.5, 136.2, 135.5, 134.8, 134.6, 130.2, 130.0, 128.5, 128.3, 127.8,
127.5, 127.3, 127.1, 127.0, 43.9; IR (neat, cm−1) 3437, 3070, 3024,
2854, 2360, 1766, 1682, 1587, 1489, 1451, 1374, 1317, 1259, 1211,
1174, 1104, 1045, 941, 910, 874, 792, 757, 695; HRMS (APCI) Calcd
for C23H18Cl M + H = 329.1092, found 329.1094.
(3-Bromocyclopenta-1,3-diene-1,2,4-triyl)tribenzene (6a). Yellow
oil, 8 mg, 10% yield (0.2 mmol scale): 1H NMR (400 MHz, CDCl3) δ
7.823−7.804 (d, J = 7.6 Hz, 2H), 7.433−7.371 (m, 5H), 7.327−7.294
(m, 3H), 7.167−7.123 (m, 5H), 3.935 (s, 2H); 13C NMR (100 MHz,
CDCl3) δ 143.0, 140.1, 139.7, 135.7, 135.4, 135.3, 130.0, 128.4, 128.4,
128.3, 127.8, 127.5, 127.4, 127.0, 120.6, 45.5; IR (neat, cm−1) 3437,
3070, 3024, 2854, 2360, 1766, 1682, 1587, 1489, 1451, 1374, 1317,
1259, 1211, 1174, 1104, 1045, 941, 910, 874, 792, 757, 695; HRMS
(APCI) Calcd for C23H18Br M + H = 373.0586, found 373.0584.
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1
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is available free of charge via the Internet at http://pubs.acs.org
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AUTHOR INFORMATION
■
Corresponding Author
*Fax: +86-931-8912582. Tel: +86-931-8912593. E-mail:
liangym@lzu.edu.cn.
Notes
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